Remove MOJO_DISALLOW_COPY_AND_ASSIGN and MOJO_ALLOW_UNUSED_LOCAL.

mojo/public/c/system/tests/macros_unittest.cc

Index: mojo/public/c/system/tests/macros_unittest.cc
diff --git a/mojo/public/c/system/tests/macros_unittest.cc b/mojo/public/c/system/tests/macros_unittest.cc
index b22e1249fa6f477e2f5847f4aedb1a13b69c0840..19fcb54085ad44638a33fae62f926f0b43f076be 100644
--- a/mojo/public/c/system/tests/macros_unittest.cc
+++ b/mojo/public/c/system/tests/macros_unittest.cc
@@ -19,12 +19,6 @@
 namespace mojo {
 namespace {
 
-TEST(MacrosTest, AllowUnused) {
-  // Test that no warning/error is issued even though |x| is unused.
-  int x = 123;
-  MOJO_ALLOW_UNUSED_LOCAL(x);
-}
-
 int MustUseReturnedResult() MOJO_WARN_UNUSED_RESULT;
 int MustUseReturnedResult() {
   return 456;